2. Click “Continue” in the confirmation window, or type the administrator password, if requested.

3.Navigate to “HKEY_CURRENT_USER\Software\Classes” in the Registry Editor. Right-click the extension under “Classes,” select “Delete” and click “Yes” in the confirmation window.

4. Navigate to “HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\FileExt.” Right-click the extension under the “FileExt” folder in the left-hand pane, and select “Delete.” Click “Yes” in the confirmation window.

5. Test that the association has been removed by double-clicking it from Windows Explorer. If it opens an associated program, then continue the procedure. If it asks you to choose a program, then the association has been removed.

6. Hold the “Ctrl” key and press “F” to search the Registry. Enter “.EXT”, replacing “EXT” with the actual extension, and press “Enter.” Right-click any folder from the right-hand pane that is named after that extension, and delete it. This step may be unnecessary, but some programs place additional entries in randomly named folders.